android答题系统（二）：实现主界面入口和查询数据

 

main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context="com.mytest.exam.MainActivity" >





    <Button

        android:id="@+id/btn_exam"

        style="?android:attr/buttonStyleSmall"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginTop="52dp"

        android:text="开始答题" />



</RelativeLayout>

View Code

 

MainActivity

package com.mytest.exam;



import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;



import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.Button;



public class MainActivity extends Activity {



    private Button btnExam;



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);



        loadDB();



        btnExam = (Button) this.findViewById(R.id.btn_exam);

        btnExam.setOnClickListener(new View.OnClickListener() {



            @Override

            public void onClick(View v) {

                Intent intent = new Intent(MainActivity.this, ExamActivity.class);

                startActivity(intent);



            }

        });

    }



    /**

     * 加载数据库

     */

    private void loadDB() {

        File file = new File(DBService.DB_PATH + DBService.DB_NAME);

        if (file.exists() == false) {

            File dir = new File(DBService.DB_PATH);

            dir.mkdir();

        }



        try {

            InputStream is = getBaseContext().getAssets().open(DBService.DB_NAME);

            OutputStream os = new FileOutputStream(file);



            byte[] buff = new byte[1024];

            int len = 0;

            while ((len = is.read(buff)) > 0) {

                os.write(buff, 0, len);

            }

            os.flush();// 必须调用

            os.close();

            is.close();



        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

    }



}

View Code

 

DBService

package com.mytest.exam;



import java.util.ArrayList;

import java.util.List;



import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;



public class DBService {



    public static final String DB_PATH = "/data/data/com.mytest.exam/databases/";

    public static final String DB_NAME = "question.db";



    private SQLiteDatabase db;



    public DBService() {

        this.db = SQLiteDatabase.openDatabase(DB_PATH + DB_NAME, null, SQLiteDatabase.OPEN_READWRITE);

    }



    public List<Question> getQuestions() {

        List<Question> list = new ArrayList<Question>();



        Cursor cursor = db.rawQuery("select * from question ", null);

        if (cursor != null && cursor.getCount() > 0) {

            int count = cursor.getCount();

            for (int i = 0; i < count; i++) {

                cursor.moveToPosition(i);

                Question question = new Question();

                question.question = cursor.getString(cursor.getColumnIndex("question"));

                question.answerA = cursor.getString(cursor.getColumnIndex("answerA"));

                question.answerB = cursor.getString(cursor.getColumnIndex("answerB"));

                question.answerC = cursor.getString(cursor.getColumnIndex("answerC"));

                question.answerD = cursor.getString(cursor.getColumnIndex("answerD"));

                question.answer = cursor.getInt(cursor.getColumnIndex("answer"));

                question.ID = cursor.getInt(cursor.getColumnIndex("ID"));

                question.explain = cursor.getString(cursor.getColumnIndex("explaination"));

                question.selectedAnswer = -1;

                list.add(question);

            }

        }

        return list;



    }



}

View Code

 

Question

package com.mytest.exam;



public class Question {

    public String question;

    public String answerA;

    public String answerB;

    public String answerC;

    public String answerD;

    public int answer;

    public String explain;

    public int ID;

    public int selectedAnswer;

    

    public String getQuestion() {

        return question;

    }



    public void setQuestion(String question) {

        this.question = question;

    }



    public String getAnswerA() {

        return answerA;

    }



    public void setAnswerA(String answerA) {

        this.answerA = answerA;

    }



    public String getAnswerB() {

        return answerB;

    }



    public void setAnswerB(String answerB) {

        this.answerB = answerB;

    }



    public String getAnswerC() {

        return answerC;

    }



    public void setAnswerC(String answerC) {

        this.answerC = answerC;

    }



    public String getAnswerD() {

        return answerD;

    }



    public void setAnswerD(String answerD) {

        this.answerD = answerD;

    }



    public int getAnswer() {

        return answer;

    }



    public void setAnswer(int answer) {

        this.answer = answer;

    }



    public String getExplain() {

        return explain;

    }



    public void setExplain(String explain) {

        this.explain = explain;

    }



    public int getID() {

        return ID;

    }



    public void setID(int iD) {

        ID = iD;

    }



    public int getSelectedAnswer() {

        return selectedAnswer;

    }



    public void setSelectedAnswer(int selectedAnswer) {

        this.selectedAnswer = selectedAnswer;

    }





}

View Code